It is commonly believed that humans exhibit lighting invariant object recognition. Here we present psychophysical evidence to the contrary. We examine the perception of qualitative local shape from shading and find that significant variations occur as a function of the lighting. These variations have two logically distinct causes: first, there are inherent ambiguities between shape and shading ...

Although recent evidence reconfirmed the importance of spectral peak frequencies in vowel identification [Kiefte and Kluender (2005). J. Acoust. Soc. Am. 117, 1395-1404], the role of formant amplitude in perception remains somewhat controversial. Although several studies have demonstrated a relationship between vowel perception and formant amplitude, this effect may be a result of basic auditor...

In this study of the informativeness of boundary contours for the perception of natural object shape, observers viewed shadows/silhouettes cast by natural solid objects and were required to adjust the positions of a set of 10 points so that the resulting dotted shape resembled the shape of the original silhouette as closely as possible. For each object, the observers were then asked to indicate...

Musical processing can be decomposed into the appreciation of global and local elements. This global/local dissociation was investigated with the processing of contour-violated and interval-violated melodies. Performance of a group of 16 children with Williams syndrome and a group of 16 control children were compared in a same-different task. Control participants were more accurate in detecting...

This document describes four projects that, taken together, serve as a proof by example of the efficacy of a perception-motivated strategy for making graphics tools. More specifically, this strategy involves first selecting local features motivated by human perception and domain understanding, and then building algorithms that allow users to interactively edit these features. While the tools pr...

The perception of biological motion is subserved by both a global process that retrieves structural information and a local process that is sensitive to individual limb motions. Here, we present an experiment aimed to characterize these two mechanisms psychophysically. Naive observers were tested on one of two tasks. In a walker detection task designed to address global processing, observers we...

This study reevaluates the role of interhemispheric interactions in the consistency effect (global interference with local decisions) in hierarchical perception. In an earlier study, Robertson et al. [22] (Neuropsychology, Vol. 7, pp. 325-342, 1993) tested three split-brain patients on a hierarchical perception task in which stimuli, consisting of large (global) letters made up of smaller (loca...

In two experiments, visual search and speeded classification were used to study perception of hierarchical patterns among participants aged 5 to 23 years. Perception of global configurations of few-element patterns and local elements of many-element patterns showed large age-related improvements. Only minor age-related changes were observed in perception of global configurations of many-element...

The brain's information processing power is limited by its energy supply but the allocation of cortical energy use between conscious and unconscious information processing is unknown. We calculate, from electrophysiological data in primates, that conscious perception reflects surprisingly small local alterations in mean cortical neuronal firing rate and energy consumption: perceiving visual sti...

Lidocaine, a local anesthetic drug, exerts its effect by blocking sodium channels in peripheral sensory neurons. It is commonly used in clinical practice as a local anesthetic drug. This study was undertaken in order to determine the effect of lidocaine on sodium channels in neurons of the central nervous system and its modulatory effect on the pain perception in rats. Therefore, the effect of ...